The present invention relates to a method for the continuous feed of a strip of material to a machine.
The present invention is particularly useful when fitted on cigarette making machines, especially filter tip application machines, which are specified in the following description, although without limiting the possibilities for application of the invention.
In the known filter tip application machines, filter tips are applied to cigarettes using bands, each of which is wrapped around and over a filter and part of a cigarette in order to form a filter cigarette.
The bands are cut from a strip of paper, normally drawn from a reel and continuously fed to the filter tip application machine by a strip feed unit.
A known technique to reduce the rigidity of the strip of paper and facilitate the winding of each band around a respective filter and cigarette is the use of paper curling devices.
A known curling device described in U.S. Pat. No. 3,962,957 includes a curling blade, positioned so that it makes contact with the strip and designed to flex the strip transversally. Flexing is effected at a curling station, positioned along a strip feed path, upstream of a device for gumming the strip and a unit which cuts the strip into the filter--cigarette bands.
During operation of the above-mentioned curling device, the strip of paper frequently broke, mainly due to the considerable load to which the strip is subjected downstream of the curling station.
In the curling station, the friction created by the blade on the surface of the strip is enough to cause sudden and uncontrollable increases in the tension of the strip as it moves towards the filter tip application machine.
Moreover, the curling blade in the said device is subject to rapid wear and so damages the strip, as well as necessitating frequent stopping of the filter tip application machine to allow substitution of the blade.